As reported in The Economist, Harvard’s Richard Wrangham has a theory that “cooking and other forms of preparing food are humanity’s ‘killer app'”:
Cooking is a human universal. No society is without it. No one other than a few faddists tries to survive on raw food alone. And the consumption of a cooked meal in the evening, usually in the company of family and friends, is normal in every known society. Moreover, without cooking, the human brain (which consumes 20-25% of the body’s energy) could not keep running. Dr Wrangham thus believes that cooking and humanity are coeval.
In fact, as he outlined to the American Association for the Advancement of Science (AAAS), in Chicago, he thinks that cooking and other forms of preparing food are humanity’s “killer app”: the evolutionary change that underpins all of the other—and subsequent—changes that have made people such unusual animals.